Most schools in the UK are probably breaking the law by failing to alert students to the scores of cameras capturing their conversations and movements in playgrounds and classrooms, a study has claimed.

Pupils in schools are as frequently monitored by CCTV cameras as inmates in prisons and customers at airports, the report by Salford University says. Most secondary schools have at least 20 cameras.

Schools have installed cameras to improve teaching, as well as detect vandalism, intruders and bad behaviour. At least one school has put cameras with microphones in classrooms and corridors, and given staff earpieces to listen in on what the cameras pick up.. It is now common for secondary schools to fingerprint pupils.

Researcher Emmeline Taylor examined surveillance practices in 24 comprehensives in north-west England and analysed the law governing CCTV use in schools as part of her PhD thesis.